My son potty trained at age 5 when he entered kindergarten due largely in part to an amazing team of aides and teachers. ASD daughter potty trained at 3.5 but still wets the bed at 13 (and she's much HF than her brother).

Our son used to tell us to put a new diaper on him at 2 or 3. He was almost 4 when actually trained. We used a probiotic to help with GI issues. A therapist trained us with Positive practice/over correction. we used a specific schedule and had pictures of toilets in the house. We stayed home completely for a few days. We did not even go to the playground. We put a pull up over underwear when we finally started to go out and pull up alone at night.. He was using the toilet independently by the end of the week. He even said that he needs a toilet while we were outside. He only had accidents when he had a GI issue after about a month.